The role of molecular rare gas ions in plasmas operated at atmospheric pressure

Molecular rare gas ions (MRIs) may offer a fast volume recombination channel in rare gas plasmas via dissociative recombination (DR). In this paper, the concentration of MRI is calculated by balancing the most important processes for formation and destruction of these ions. It is shown that the effective loss frequency of charged particles in the plasma due to DR of MRI is not determined by the formation of these ions, but by the DR process itself. Also the consequences for the particle and energy balances of atmospheric 'size-stabilized' helium and argon plasmas are discussed, as well as the influence on the lower boundary for partial local Saba equilibrium.